1. Field of the Invention
The present invention relates generally to a rotational balance adjustment mechanism for a rotary head drum device.
2. Description of the Related Art
Typically, apparatuses such as a videotape recorder (VTR) or a digital audio tape recorder (DAT), for example, are equipped with a rotary head drum device consisting of a fixed drum and a rotary drum. In addition, the magnetic tape must be wound helically around the rotary head drum, so the rotary drum is mounted on the main chassis at an angle thereto as a result.
Conventionally, a balance weight is mounted as one method for adjusting the rotational balance of the rotary drum of a rotary head drum device such as that described above.
However, although conventional rotary drum rotation speeds have been on the order of approximately 2000 RPM, the need for ever-faster tape data transfer rates (typically measured in MB/s) now necessitates rotational speeds on the order of 10,000 rpm or more.
Given such increased rotational speeds, the conventional rotational balance adjustment method has not always proved satisfactory. In particular, the rotary transducer provided at a position removed from the fixed portions of the rotary drum and shaft has been susceptible to imbalances. Such imbalances in the rotary transducer can cause fluctuations in the height of the magnetic head provided in the vicinity of the transducer, such that the magnetic head deviates from its assigned position and aversely affects reproduction and recording characteristics. Additionally, the joints of the head may come apart due to excessive vibration.
Accordingly, it is a general object of the present invention to provide an improved and useful rotational balance adjustment mechanism for a rotary head drum device in which the disadvantages described above are eliminated.
Another, further and more specific object of the present invention is to provide an improved and useful rotational balance adjustment mechanism for a rotary head drum device in which vibration generated when the rotary drum rotates at high speed can be effectively reduced, and in particular, in which fluctuations in the height of the magnetic head can be effectively restrained.
The above-described objects of the present invention are achieved by a rotational balance adjustment mechanism for a rotary head drum device having a fixed drum, a shaft rotatably driven by a motor provided on the fixed drum, a rotary drum mounting a magnetic head, the rotary drum rotating atop the fixed drum, and a rotary transducer having a fixed transducer member provided on the fixed drum and a rotating transducer member provided on the rotary drum, the rotating transducer member adapted to mount a balance weight for adjusting the rotational balance of the rotary drum.
Additionally, the above-described objects of the present invention are also achieved by a rotational balance adjustment mechanism for a rotary head drum device including a fixed drum, a shaft rotatably driven by a motor provided on the fixed drum, a rotary drum mounting a magnetic head, the rotary drum rotating atop the fixed drum, a rotary transducer having a fixed transducer member provided on the fixed drum and a rotating transducer member provided on the rotary drum, and a mounting member mounted on the rotating transducer member, the mounting member adapted to mount a balance weight for adjusting the rotational balance of the rotary drum.
In the invention described above the mounting member may be a printed circuit board or the like provided with electrodes for electrically connecting the magnetic head and the rotating transducer member, the printed circuit board being mounted on the rotating transducer member.
According to the invention described above, balance weight for rotational balance adjustment can be mounted as appropriate, thus effectively reducing the vibrations generated when the rotary drum rotates at high speeds, and in particular reducing fluctuations in the height of the magnetic head. As a result, the adverse effects on the recording and reproduction characteristics of the magnetic head deviating from its assigned position and the coming apart of the head at the joints caused by excessive rotational vibration are also reduced.
Additionally, the above-described objects of the present invention are also achieved by the rotational balance adjustment mechanism for a rotary head drum device as described above, wherein the balance weight is mounted at an arbitrary position at a predetermined distance along an outer periphery of the rotating transducer member.
Additionally, the above-described objects of the present invention are also achieved by the rotational balance adjustment mechanism for a rotary head drum device as described above, wherein the balance weight is mounted at an arbitrary position at a predetermined distance along an outer periphery of the mounting member.
According to the invention described above, one or more balance weights of the desired amount can be easily mounted at any desired position along the outer periphery of the rotating transducer member or mounting member, making fine adjustment of the rotational balance possible.
Additionally, the above-described objects of the present invention are also achieved by the rotational balance adjustment mechanism for a rotary head drum device wherein the balance weight can may be made of solder or resin.
According to the invention described above, the use of solder as the balance weight means that the balance weight does not easily come unseated from and fly off the rotating transducer member or the mounting member, as the case may be. Additionally, the use of resin as the balance weight means that a cheap, relatively easily mountable material can be used to carry out rotational balance adjustment.
Additionally, the above-described objects of the present invention are also achieved by the rotational balance adjustment mechanism for a rotary head drum device as described above, wherein the balance weight or mounting member can be variably shaped.
According to the invention described above, fine adjustment of the rotational balance can be achieved with ease, simply by shaving or bending the balance weight to achieve the desired balance. Similarly, the mounting member may also be simply bent to achieve the desired balance.
Additionally, the above-described objects of the present invention are also achieved by the rotational balance adjustment mechanism for a rotary head drum device as described above, further having a guard member to prevent the balance weight from becoming unseated and flying off the rotational balance adjustment mechanism.
According to the invention described above, the possibility that the balance weight may become unseated from and fly off the rotational balance adjustment mechanism at high rotational speeds may be further prevented.